This invention relates to a structure of fluid condensing and heat conducting surface of the plate type and tube type condensers.
Many of plate type condensers now in use have been developed from the plate type heat exchangers for exclusive use in processing of fluid-to-fluid system. A problem in the improvement of heat conducting performance of the condenser of this type is the coefficient of border filmy fluid layer which represents a degree of heat conduction on the heat conducting surface. This coefficient is expressed in terms of (heat conductivity of border filmy fluid layer/thickness of said layer), which is determined by the state of sticking of condensing fluid (vapor) to the heat conducting surface. In other words, when vapor is fed to the heat conducting surface which forms vapor flow path, small drops of fluid generates as a result of condensation of vapor in the form of filmy layer on the whole of said surface and grow larger with the continuance of condensation, finally falling down along said vertical surface by acceleration due to the weight of themselves and wind pressure caused by flowing vapor. This filmy fluid layer grows thicker as it falls downward, thereby intercepting contact of the heat conducting surface with vapor, and causes significant reduction of border layer coefficient which leads to a remarkable decrease of heat conducting efficiency. Therefore, for the improvement of heat conducting performance (total coefficient) on which vapor condenses, it is necessary to provide a device to reduce the surface area of falling filmy fluid layer as far as possible and prevent said layer from growing thicker.